Changing water regime and adaptation strategies in Upper Mustang

Transcription

Changing water regime and adaptation strategies in Upper Mustang
http://www.scar.ac.cn
Sciences in Cold and Arid Regions
2013, 5(1): 0133–0139
DOI: 10.3724/SP.J.1226.2013.00133
Changing water regime and adaptation strategies in Upper
Mustang Valley of Upper Kaligandaki Basin in Nepal
Prem Sagar Chapagain 1*, Jagat K. Bhusal 2
1. Central Department of Geography, Tribhuvan University, Kathmandu, Nepal
2. Chairperson, The Society of Hydrologists and Meteorologists Nepal, Kathmandu, Nepal
*Correspondence to: Prem Sagar Chapagain, Ph.D., Associate Professor, Central Department of Geography, Tribhuvan University, Kathmandu, Nepal. E-mail: [email protected]
Received: October 30, 2012
Accepted: January 20, 2013
ABSTRACT
Recent climate change has brought changes to the water regime that has affected the traditional agro-pastoral production systems
and livelihoods in the Upper Kaligandaki Basin of the Nepal Himalayas. Based on fieldwork and available meteorological and
hydrological data, this paper examines the changing water regime and various adaptation strategies that local farmers have adopted in this cold arid region. Increasing temperature and decreasing rainfall and snowfall have resulted in a negative water balance.
In this scenario, farmers have implemented six major adaptive strategies in the trans-Himalayan Upper Mustang Valley.
Keywords: Upper Kaligandaki; farming; livelihoods; climate change; water balance; adaptation strategies
1 Introduction
Climate change is a matter of global concern. The average
global temperature rose by 0.74 °C over the last hundred years
(1906–2005) (IPCC, 2007), and the average rate of warming in
the Nepal Himalayas is 0.4 °C per decade. Changes in the Himalayas could affect the lives and livelihoods of more than 1 billion people living in the river basins downstream. There is
clearly rising trend of temperature in Nepal and it is more
prominent in higher altitude regions of the country (Shrestha et
al., 1999). Recent studies show the progressively higher warming in higher altitude of the whole Himalaya and the rate of
temperature rising is 0.01 °C in the eastern Himalayas (New et
al., 2002; Shrestha and Devkota, 2010). Climate change impacts
are strong, both positive and negative, and they directly affect the
high Himalayan agro-pastoral-based communities, especially
their water requirements for drinking and irrigation, food production, and food security.
Climate change effects on food production suggest that
agriculture productivity will increase at temperate high latitudes, and it will decrease at lower latitudes of tropical and
subtropical areas (Cline, 2008; Cribb, 2010). It has been
predicted that agriculture production in temperate countries
in the north could increase by 8% to 25% by 2050, whereas
in the south, especially in India, it will decrease by 30%
(Cline, 2008). In this context, this paper examines the water
regime in the cold arid region of the Upper Kaligandaki
Basin and the local adaptation strategies of
agro-pastoral-based production systems in the region.
Bordered by the Tibet Autonomous Region of China to the
northeast, the Upper Kaligandaki Basin is located in the
trans-Himalayan region of Nepal (Figure 1). The Himalayas are
geologically young, fragile, and subject to continuous denudation. The mountains’ steep slopes and many river gorges preclude dense settlements, and arable land is limited (NTNC,
2008). The basin covers an area of 3,200 km2, with an elevation
ranging from 2,800 to 8,168 m a.s.l.
The basin lies in a rain shadow and receives very little
rain, less than 300 mm annually (DHM, 1999). The climate of
the district is generally dry with strong winds and intense
sunlight. The maximum temperature that has been recorded
in summer is 26 °C and the winters are very cold, with temperatures ranging to −20 °C.
In 2010 a seasonal road was built to the once-inaccessible
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High Mountain area. This has not only created growth opportunities but has also widened economic disparity gaps, accelerated environmental degradation, heightened cultural integration, and contributed to the haphazard growth of settlements
which were already begun to notice (Tulachan, 2001). Although the lower part of the area lies within the world-famous
Annapurna Trekking Circuit, local settlements have benefited
little from tourism because of their off-route locations. Therefore, the means of livelihood in the cold and arid zones of
Nepal in general, and specifically in the Mustang Valley, continue to reflect adaptation for survival in the context of global
warming and habitat degradation (Simon, 2010).
Figure 1 Upper Kaligandaki Basin in the Mustang Valley, Nepal
2 Methods and materials
This study was based on analysis of available rainfall,
temperature, and river discharge data of the Nepal government’s Department of Hydrology and Metrology. We utilized continuous data from four monitoring stations, Muktinath, Lomanthang, Ghami, and Jomsom, of the Upper
Mustang Valley from 2000–2012. Water balance was calculated using parameters such as rainfall, outflow, evapotranspiration, and deep percolation. Data on evapotranspiration and deep percolation were not available in the basin, so
the water balance was calculated based on total rainfall minus outflow. The outflow data were available from the
gauge station of Kaligandaki River at its outlet in Upper
Mustang Valley at Jomsom.
In addition, two weeks of fieldwork were conducted in
January 2011 in the Tiri, Phalek, and Dhagarjung villages in
the Upper Mustang Valley. These villages are about two and
a half hours’ walking distance from the Jomsom airport.
Data were collected using questionnaire surveys, focus
group discussions, personal observations, and key informant
interviews. There are 47 households in Dhagarjung, 68 in
Phalek, and 23 in Teri. Of these, 10 households from each of
the three villages were randomly selected for the questionnaire survey. One focus group discussion and one key informant interview were conducted in each village.
3 Discussion
3.1 Water regime
The upper part of the Kaligandaki Basin lies in a rain shadow and receives very little precipitation. Annual precipitation
over the area near the basin outlet is 300 mm, whereas the driest
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part of the basin gets only 145 mm annually (DHM, 1999, 2000).
The area between 2,800 and 3,000 m a.s.l. has a cold temperate
climate and is the wettest part. Tundra ranges above 5,000 m a.s.l.
and is covered with snow year-round. The climate of the district
is generally dry with strong winds and intense sunlight. The
winters are very cold, with temperatures ranging to −20 °C.
Climate change is a matter of global concern. Recent preliminary research indicated that the temperature in the study area
has a rising trend of about 0.02 °C per year (Baidya et al., 2008;
Practical Action Nepal, 2009), while the lower part of the Upper
Kaligandaki River Basin has incurred an increasing trend in
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annual precipitation (Gauchan, 2010). Based on observed
monthly precipitation, the annual volume of water is 705 million
cubic meters, but the water balance is negative and is emptying
by 355 million cubic meters annually in the study basin.
We analyzed observed Kaligandaki River flow data and
precipitation data of the basin (DHM, 2010) from the climate change perspective. There are clear indications of climate change effects on local water regimes. The annual
runoff volume that is discharging out through the basin and
the total annual volume of water falling over the basin area
(3,200 km2) as precipitation are summarized in Figure 2.
Figure 2 Annual runoff and rainfall volume from the 3,200 km2 area of the basin The long-term mean annual precipitation computed by
arithmetic mean is 220 mm, which is equivalent to 705 million cubic meters. The annual water volume discharging out
of the basin amounts to 1,060 million cubic meters (DHM,
2008). The water balance is negative and is emptying by 355
million cubic meters annually. Our analyses of recent data
(2000–2012) indicated that except during the pre-monsoon
months (March, April, and May), runoff exceeded precipitation inputs (Figure 2, Table 1).
The runoff/rainfall ratio is approximately 1.50. Theoretically, the natural runoff/rainfall ratio should be close to 1.0,
but due to evapotranspiration, deep percolation, and other
losses, the ratio never actually reaches 1.0. An assessment
made on the Kosi River in Nepal found that there is about an
8.46% contribution to annual flow from snow and glacier
melt: a maximum monthly contribution of 22.52% in May
and a minimum monthly contribution of 1.86% in January
(WWF, 2009). However, the recorded rainfall over the
Kaligandaki River Basin may not be accurately representative due to rare information on precipitation (annual snowfall) records above 4,000 m a.s.l. Also, runoff contributing to
groundwater aquifers could originate outside of the basin.
However, there are clear indications that snow and glacier
contribution, including groundwater contribution, is appreciable in the study basin. The present study found that the
snow melt contribution in the Upper Kaligandaki River Basin could reach up to 40% (Figure 3). This suggests that
environmental conditions could worsen if temporal and spatial variations become wider due to climate changes and
warming in the future.
Table 1 Seasonal volume of water (input and output) at the Upper Kaligandaki Basin
Seasons
Pre-monsoon
Precipitation (MCM)
104
River flow (MCM)
104
Note: MCM = Million cubic meters.
Monsoon
443
748
3.2 Livelihood and adaptation strategies
Historically, water has been considered a productive and
Post-monsoon
65
112
Winter
93
96
Annual Total
705
1,060
symbolic resource in this basin (Hamilton, 1819). Water
has been highly contested between individuals, communities, and social groups, and water rights were closely tied
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with the fraternal polyandry system of marriage practiced
until recently in the region. Although this marriage system has almost died out by now, the impartible inheritance system has left the people divided into social classes (Basnet, 2007).
Traditional agro-pastoral production systems focus on
growing cereal crops, i.e., wheat, buckwheat, potatoes, and
barley. In addition, herdsmen keep livestock such as yaks,
goats, sheep, and cattle. Both of these systems have been
affected by climate change and globalization. The decline in
water sources (springs and streams) is of great concern in
this basin because people living there depend greatly on the
local environmental resources to eke out their living. Importantly, climate change is altering snowfall amounts,
which in time results in less water available for irrigation for
the traditional agro-pastoral production system. People
freely graze livestock on highland pasture land but, given the
very low moisture-holding capacity of the soil, the grazing
productivity has been decreasing in line with changing
snowfall and rainfall patterns. Sharp declines in snowfall
and water have severely affected the pasture productivity,
which in turn has negatively affected the whole farming and
livelihood diversification. In response, local people have
implemented the following adaptive strategies.
Figure 3 Decrease in river flows, snow-fed and non-snow-fed rivers in Nepal
Strategy 1: Set new community rules and regulations for
irrigation water use
Farmers have established a new water governance system and set new rules for irrigation water utilization. Traditionally, each village constructed one large pond to store
stream water for gravity irrigation to the surrounding farmland. As recently as 15 years ago, one household could
completely irrigate its own farmland and then the next
household could completely irrigate its land. Now there is
not sufficient water stored in such ponds, so each household
gets irrigation water for a fixed number of hours (3–4 hours),
irrespective of the farm size and its distance from the water
storage pond. The time duration decreases depending upon
the amount of water available at the stream and stored in
the pond. Because of this rule, farmers whose agricultural
land is far from the village are deprived as they get the
least water.
Strategy 2: Construct new water infrastructure
Traditionally, farmers constructed mud wall ponds for
storing water. However, water infiltration is high through the
local coarse colluvium soil, so it was necessary to first cement the canals from the spring sources to the ponds. Recently, farmers have started to replace the traditional mud
ponds with concrete water storage tanks (Figure 4).
Farmers have also started to lift Kaligandaki River water up to their villages. In Teri village they installed an
electric motor and a pipe at the river bank and now lift
water to the top of the village, enabling gravity irrigation.
This success has encouraged other villages in the Upper
Mustang Valley to do the same. In addition, farmers have
constructed series of irrigation ponds on the mountain
slope so that water that leaks from the storage pond can be
captured in the downslope ponds and brought back to the
village by a new canal.
Strategy 3: Gradually adopt new farming systems
It has already mentioned that, as previously described,
the farmers in this region have traditionally grown limited
crops such as wheat, buckwheat, potatoes, and barley. Previously, it was unthinkable to plant cash crops on cereal-growing land. Now this has been made possible by increasing temperatures and also by newly available markets
and road transportation. Therefore, many farmers have
started growing apples instead of cereal crops (Figure 5).
This has proven to be economically beneficial and is the best
option given the lack of water and the local labor shortage.
In addition, farmers have started to grow many vegetables
such as tomatoes, beans, carrots, onions, garlic, pumpkins,
spinach, and coriander, especially in Teri village. There is
Prem Sagar Chapagain et al., 2013 / Sciences in Cold and Arid Regions, 5(1): 0133–0139
high demand for such vegetables at local markets due to the
increasing tourist use of the Annapurna Circuit, which is the
first trekkers’ destination in Nepal and where about 90,000
tourists visit annually. Farmers are able get more income in
comparatively less growing time. The local NGO, mainly
the Annapurna Conservation Area Project (ACAP), and
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relatives and friends have encouraged these farmers by
providing knowledge and other support; this farming system
change is also supported by the government. Thus, changes
in income and cropping patterns, as well as systemic changes in farming methods, are now taking place in the Upper
Mustang Valley.
Figure 4 Traditional mud pond (left), and modern concrete tank (right) at Teri village
Figure 5 Apple plantations on former cereal-growing land in Teri village
Strategy 4: Adopt new irrigation methods on planting
terraces
Climate change is a long process. Farmers have observed less snow on mountains and water in streams, which
has compelled them to adopt new production strategies at
the local level. For example, farmers have adapted by
changing their traditional irrigation systems. As previously
mentioned, high mountain areas have glacier-deposited soil
that is coarse and water infiltration through it is high. In the
past, there was sufficient water so farmers needed only one
or two planting beds within a single terrace. Given the current situation of water scarcity, farmers have reduced the
breadth of planting beds in their terraces; in Figure 6 the
distance between bed A and bed B has decreased. As shown
in the photo, a water canal enters from C and irrigates the
planting beds. To irrigate bed A, canal water directly enters
from D, and also the accumulated water on bed B flows to
bed A via C. It is important that only small amounts of water
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be introduced at a time, rather than irrigating the whole terrace or even an entire planting bed at once. This prevents
water loss from percolating downward through the coarse
and sandy soil. This sort of technical knowledge was been
developed by the farmers’ experience with the soils in this
region.
A
B
D
C
Figure 6 Smaller planting beds in a terrace for water optimization in Teri village
Strategy 5: Abandon less productive land and distant land
Another adaptive strategy to water scarcity is land
abandonment. Farmers have abandoned about 0.2 hectare of
land per household in Dhagarjung and Teri villages and
about 0.5 hectare per household in Phalek village. Land
abandonment is very high in Phalek village, where each
household has abandoned about 0.5 hectare of cultivated
land within the last 15 years (Figure 7). As shown in the
photo, farmers first abandoned distant cultivated land and
thereafter land nearer to the village. This is primarily due to
the water shortage, but is also the result of labor shortage as
young people are no longer interested in agriculture. They
prefer to either move to cities for employment or emigrate
for foreign work opportunities.
Figure 7 Old and newly abandoned cultivated land in Phalek village
Strategy 6: Seasonal migration for household income
In the study villages, virtually every household partici-
pates in either short- or long-term seasonal migration to urban
areas or to foreign countries for household income. Out of the
Prem Sagar Chapagain et al., 2013 / Sciences in Cold and Arid Regions, 5(1): 0133–0139
total households of the Mustang district (3,305), 26.4 percent
of households have recorded absent household member who
has been living outside home for more than six months. The
total population of such absent population is 10.6 percent of
the total population of the district in 2011. Out of this absent
population, male constitutes 69.2 percent. (CBS, 2012). In
addition, during the off-agricultural season many people,
mostly women, go to the cities of Gauhati and Dehradun in
northeastern India for employment, while men involved in the
food and livestock business work in the Dolpa district in Nepal.
Due to recent environmental changes and their effects on agriculture, such migration is fairly compelled; young people now
rarely live at home and participate in traditional farming activities. Thus, agriculture has become the sole responsibility of
women and aged household members. However, farm laborers
from Dolpa, Rukum, the Upper Mustang Valley, and Myagdi
reverse-migrate during the planting and harvesting times.
4 Conclusions
Although climate change is a long-term process, it has
already severely affected the water sources of the Upper
Kaligandaki Basin. The trends of increasing temperature and
decreasing precipitation in this cold arid environment will
have long-term implications for infrastructure, regional geomorphology, and eventually the entire ecosystem. Local
residents continually adopt various response strategies based
upon their knowledge, experiences, and opportunities at the
local level. The increasing tourism activities, development
of roads, and possibilities of growing new crops are some
positive aspects of these recent changes. Therefore, research
studies at the local level are important to understand the
wide range of adaptation mechanisms and challenges in the
mountain regions of Nepal.
Acknowledgments:
We are thankful to UNESCO IHP for the financial support
for hydrological research in the Upper Kaligandaki Basin in
2011.
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